Light collector for photosensitive element



Sept. 11, 1956 G. W. ONKSEN, JR., ET AL LIGHT COLLECTOR FORPHOTOSENSITIVE ELEMENT 3 Sheets-Sheet 1 Original Filed Dec. .28, 19483nvenlocs (Zttorneg Sept. 11, 1956 2,762,930

G. W. ONKSEN, JR., ET AL LIGHT COLLECTOR FOR PHOTOSENSITIVE ELEMENTOriginal Filed Dec. 28, 1948 3 Sheets-Sheet 2 Gttornegs Sept. 11, 1956G. w. ONKSEN, JR, ET AL 2,762,930

LIGHT COLLECTOR FOR PHOTOSEINSITIVE ELEMENT Original Filed Dec. 28, 19483 Sheets-Sheet 3 gig/5 attorneys LIGHT COLLECTOR FOR PHOTOSENSITIVEELEMENT George W. Onksen, in, Charles W. Miller, and Robert N.

Falge, Anderson, Ind., assignors to General Motors Corporation, Detroit,Mich., a corporation of Delaware Application April 29, 1954, Serial No.426,517

'11 Claims. (Cl. 250-215) This is a continuation of my co-pendingapplication Serial No. 67,722 filed December 28, 1948, now abandoned.

The present invention relates to light-responsive devices and moreparticularly to an improved light collector for photoelectric cells.

Automotive vehicle illuminating systems provided with means responsiveto the light of an oncoming vehicle for automatically controlling theenergization and deenergi- Zation of the high and low beam filaments ofthe headlamps have not been entirely satisfactory because of the lack ofsuitable means for selectively distinguishing between the headlights ofan oncoming vehicle and such other highway conditions as the backreflection of light off the highway surface due to the vehicles ownheadlights and light sources of varying intensities usually foundadjacent country highways. To be satisfactory it is considered that sucha system should be adapted to selectively distinguish between theaforementioned lighting conditions and in addition be responsive to citylighting conditions to effect an automatic dimming of the vehicleheadlights for city driving.

Accordingly it is an object of the present invention to provide in alight-responsive automatically controlled illuminating system animproved means to selectively distinguish optimum lighting conditionsfor the actuation of the illuminating system.

Another object is to provide an improved light collecting device forphotoelectric cells in the light-responsive automatically controlledvehicle illuminating systems which will protect the cell from exposureto substantially all highway lighting conditions other than thosedesired to effect a dimming of the vehicle headlights.

These and other objects are attained in accordance with the presentinvention by providing an improved photoelectric cell enclosingstructure having an optical system comprising a condensing lens and anaperture for transmitting light to the light-responsive element of thephotoelectric cell.

Further objects and advantages of the invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize the invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification. I

For a better understanding of the invention reference may be had to theaccompanying drawings in which:

Figure 1 is a perspective view of a photoelectric cell enclosureembodying the present invention;

Figure 2 is a plan view in section of the enclosure with a photoelectriccell illustrated therein;

Figure 3 is a view taken along the line 3-3 of Figure 2;

Figures 4 and 5 are fragmentary views in section of the enclosureillustrating lens interchangeable with the lens of Figures 1, 2 and 3;

Figure 6 is a plan view in section and partly broken away of amodification of the present invention;

tates Patent 0 2,762,930 Patented Sept. 11, 1956 Figure 7 is a viewtaken along the line 7-7 of Figure 6;

Figures 8 and 9 are fragmentary views in section of the enclosure ofFigures 6 and 7 illustrating lens interchangeable with the lens of thismodification;

Figure 10 is a plan View in section and partly broken away of anothermodification of the present invention;

Figure 11 is a view taken along the line 11-11 of Figure 10;

Figure 12 is a fragmentary view in section of the enclosure of Figures10 and 11 illustrating a lens interchangeable with the lens of themodification of Figures 10 and 11;

Figure 13 is a plan view in section and partly broken away of stillanother modification of the present invention;

Figure 14 is a view taken along the line 14-14 of Figure l3; and

Figure 15 is a view showing the collecting device mounted in positionbehind the windshield of a vehicle.

Referring now the the drawings and particularly to Figures 1, 2 and 3,there is illustrated an enclosing housing for photoelectric cellsadapted to provide energization of the light-responsive element of thecell under predetermined extraneous lighting conditions. The cellhousing comprises upper and lower complementary housings 2 and 4respectively, with the upper enclosing member 2 being formed with aflared band 6 adjacent its edges providing a seating shoulder 7, seeFigure 3, for engaging the edges of the lower enclosing member 4. Withthe upper and lower enclosing members in assembled position a windowaperture 8 is provided at one end for receiving a light-transmittingcondensing lens 16. Where the housing is to be used with a vehicleillumination system for control of the high and low beam filaments ofthe headlamp, it may be attached to a suitable part of the vehicle by abracket 12 which is fastened to the lower enclosing member 4 by suitablefastening members 14. in vehicle applications where the vehicle isoperated from the lefthand side and trafiic moves in lanes to the right,it is desirable to mount the photoelectric cell housing on the lefthandwindshield post of the vehicle behind the windshield so that thelongitudinal axis of the cell or tube is substantially parallel to thetransverse axis of the vehicle and the optical axis of the lens issubstantially parallel to the longitudinal axis of the vehicle. This isshown in Fig. 15 wherein 9 is a vehicle having windshield 11, the lightgathering unit 13 being secured to windshield post 15 by means of thebracket 12 so that the condensing lens 10 faces or looks through thewindshield. In this position the photoelectric cell housing is moresusceptible to exposure to the lights of an oncoming vehicle. In thisconnection we have found that the most satisfactory position for thehousing is behind the lower left-hand corner of the windshield. Toprovide for limited angular adjustment of the housing on its bracket 12,the bracket may be provided with at least one aperture having an oblongarcuate configuration concentric to the other bracket aperture.

The upper and lower enclosing members 2 and 4 are provided withcomplementary partitions 16 and 18 respectively, which cooperate todivide the assembled housing into two compartments 1'7 and 19, the firstfor receiving and positioning a photoelectric cell 20 and the latter fortransmitting light to the cell. A window 22 formed by the complementarypartition members 16 and 18 is provided for communication between thetwo compartments 17 and 19.

An optical system for directing light onto the cathode 24 of the cell21) is provided in the light-transmitting compartment 19 and comprisesthe lens 11 side reflector panels 26 and 28 and a rectangular aperture30. In Fig- 3 ures 2 and 3 the lens 10 is illustrated as a plano-convexcylindrical lens provided with recessed shoulders 32 adjacent its endsfor positioning the lens in the aperture 8 with the plane surface of thelens facing the light-transmitting compartment. Flanges 34 are formed inthe upper and lower enclosing members 2 and 4 to provide an abuttingflange for the side edges of the lens. The reflector panels 26 and 28and the rectangular aperture 30 are formed preferably in a metalstamping formed to the configuration shown. The panels are provided withears 36 for attaching the stamping to the lower enclosing member 4 byfastening members 38. provide additional abutting stops for supportingthe lens in aperture 8, the reflector ends 4-6 of the metal stamping areoutturned and the formed stamping is positioned with the outturned endsadjacent the ends of the lens 19.

The photoelectric cell 26 is mounted in the cell compartment 17 of theassembled housing by means of a socket 42 which is held by a bracket 44attached to the lower enclosing member 4 by fastening member 46.Conductor wires 48 are brought into the housing for connection with theterminals of the socket 4-2 through an aperture 5:) in the lowerenclosing member 4. To hold the photoelectric cell 26 securely in itscompartment 17, complementary supports 54 having semi-circularsupporting surfaces are formed in the upper and lower enclosing members2 and 4 for cooperation with a band 56 of shock insulating materialsurrounding the base of the cell. Bolt holes 53 are provided in thelower enclosing cell for securing the upper and lower enclosing membersin assembled relationship.

With an enclosing housing having an optical system such as that shownand described, it is considered desirable that the system transmit lightemanating from the headlamps of an oncoming vehicle to thelight-responsive cathode of the tube 20 and exclude the transmission oflight emanating from a source below the longitudinal axis of the vehiclesuch as the back reflected light of the vehicles own headlights.Further, it is considered desirable that the system be adapted toexclude the transmission of light emanating from high intensityoverhanging highway light sources immediately ahead of the vehicle. Toaccomplish these desirable results the coinciding axes of the anode 6iand the cathode 24 are aligned on the focal axis of lens 19 withaperture 39 spaced between the tube Ztl and lens it) at the foci of thelens. In this connection we have found that optimum results are obtainedby positioning the aperture 3% with its longitudinal centerline parallelwith and below the line focus of the lens. The width of the aperture 3bis predetermined to provide a vertical angular spread for lightreception to the cell of substantially eight degrees within whichextraneous light will be transmitted to the cathode of tube 20. Furtherby offsetting the longitudinal centerline of the aperture 39 below theline focus of the lens as shown in Figure 3, provision is made for thetransmission of light to the cathode emanating from an extraneous sourceWithin a vertical angle of substantially two degrees below the focalaxis of the lens and six degrees above (see Figure 15). As shown in thedrawings, the length of aperture 30 is made to correspond with thelength of the cathode to permit transmission of light to the cathodethroughoutits entire length. The length of aperture 30, however, alongwith the length of aperture 8 will determine the horizontal angle withinwhich rays from a light source outside of the housing and within thisangle will be transmitted to the cathode. We have found that this anglemay be as large as forty degrees and as small as fifteen degrees forsuitable operation in a light-responsive automatically controlledvehicle headlighting system. However, for the most desirable results itis preferred that the angle be about twenty-four degrees. With thecylindrical lens 19 illustrated in Figures 1, 2 and 3 it will beunderstood that light rays entering the lens near its ends and normal tothe front face are reflected by the reflector panels 26 and 28 anddirected to the cathode 24 through the aperture 30 thereby improving theefficiency of the light-transmission to the cathode;

In Figures 4 and 5 respectively, there is illustrated a plane-convexcylindrical lens 62 and a double-convex cylindrical lens 64 positionedin the aperture 8 of the photoelectric cell housing. In both lenses theinner lens surface is stepped to reduce the lens section. Both of theselenses would be suitable as substitute lenses in the 7 optical systemdescribed in connection with Figures 1, 2 and 3 and would providesubstantially the same optical characteristics in the system.

Figures 6 and 7 of the drawings illustrate a modification of the presentinvention in which the reflector panels 26 and 28 and the lens 10 ofFigures 2 and 3 are replaced by a plane-convex spherical lens 66. Inthis modification the lens 66 will form a point focus on the apertureinstead of the line focus of the lens 10. This is considered desirablein that the reflector panels 26 and 28 may be entirely eliminated andfurther that the horizontal angle within which light from an outsidesource may be transmitted to the cathode is determined by the length ofaperture 30.

Figures 8 and 9 respectively illustrate a plane-convex spherical lens 68and a double-convex spherical lens 70 positioned in the aperture 8 ofthe cell housing. In both of these lenses the inner surface is alsostepped to reduce the lens section. Both of these lenses would besuitable as substitute lenses in the optical system shown and describedin connection with Figures 6 and 7.

ln Figures 10 and 11 there is illustrated another modification in whicha plano-convex cylindrical lens 72 is provided with prisms 74superimposed on the plane surface. In this modification the prisms areprovided to redirect light entering the end of the lens therebyeliminating the need for reflector panels 26 and 28.

Figure 12 illustrates a lens 76 similar to lens 72 of Figures 10 and llexcept that the inner surface of the lens is entirely prismatic.

In Figures 13 and 14 there is illustrated still another modification ofthe present invention in which the lens 78 is a double cylindrical lenswith the axes of the cylindrical surfaces angularly disposed by degrees.As will be seen from the illustrations in Figures 13 and 14 light raysparallel with the axis of the front surface of the lens and entering thelens above or below the axis will be focused on the aperture 30 whilelight rays parallel with the focal axis of the rear surface of the lensand entering the lens to the right or left of the axis will be focusedon a point on or behind the cathode 24 thus making reflector panels 26and 28 unnecessary.

In connection with the descriptions of the various modifications it willbe understood that each of the modifications is provided with an opticalsystem adapted to ac complish the desirable results described inconnection with Figures 1, 2. and 3.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope of the claims whichfollow.

What we claim as new and desire to obtain by Letters Patent of theUnited States is:

l. A light collector for a vehicle headlamp dimming device comprising ahousing having an opening therein, adjustable mounting means on saidhousing adapted to cooperate with said vehicle for adjustably securingsaid collector on said vehicle so that said opening faces toward thefront of the vehicle for the reception of light, a photosensitiveelement in said housing facing said opening and means for directinglight from sources in front of the vehicle on which said collector ismounted to said photosensitive element, said last-named means comprisinga light condensing lens in said opening and an opaque part1- tionhavinga horizontally disposed elongated aperture therein positioned insaid housing between said opening and said photosensitive element anddividing said housing into two compartments, said aperture being locatedsubstantially at the focal plane of said lens in alignment with saidlens and said photosensitive element and providing the sole means foradmitting light to said photosensitive element from said opening.

2. A light collector for a vehicle headlamp dimming device as recited inclaim 1 and in which the longitudinal axis of the aperture is positionedbelow the focal axis of the lens.

3. A light collector for a vehicle headlamp dimming device as recited inclaim 1 and in which the lens is a cylindrical condensing lens.

4. A light collector for a vehicle headlamp dimming device as recited inclaim 1 and in which the lens is a stepped spherical condensing lens.

5. A light collector for a vehicle headlamp dimming device as recited inclaim 1 and in which the lens has a cylindrical surface on one sidethereof and a prismatic surface on the oppositely disposed side thereof.

6. A light collector for a vehicle headlamp dimming device as recited inclaim 1 and in which the lens has oppositely disposed cylindricalsurfaces disposed at a 90 angle with respect to each other.

7. A light collector for a vehicle headlamp dimming device comprising ahousing having an opening therein, adjustable mounting means on saidhousing adapted to cooperate with said vehicle for adjustably securingsaid collector on said vehicle so that said opening faces toward thefront of the vehicle for the reception of light, a photosensitiveelement in said housing facing said opening and means for directinglight from sources in front of the vehicle on which said collector ismounted to said photosensitive element, said last-mentioned meanscomprising a spherical light condensing lens in said opening and anopaque partition having a horizontally disposed elongated aperturetherein positioned in said housing between and spaced from said openingand said photosensitive element and dividing said housing into twocompartments, said aperture being located substantially at the focalplane of said lens in alignment with said lens and said photosensitiveelement and providing the sole means for admitting light to saidphotosensitive element from said opening.

8. In an automotive vehicle having a windshield, a light collector for aheadlamp dimming device comprising a housing having an opening therein,adjustable mounting means on said housing securing said collector onsaid vehicle behind the windshield thereof so that said opening facessaid windshield for the reception of light therethrough, aphotosensitive element in said housing facing said opening and means fordirecting light from said opening to said photosensitive element, saidlast-mentioned means comprising a light condensing lens in said openingand an opaque partition having a horizontally disposed elongatedaperture therein positioned in said housing between said opening andsaid photosensitive element and dividing said housing into twocompartments, said aperture being located substantially at the focalplane of said lens in alignment with said lens and said photosensitiveelement and providing the sole means for admitting light to saidphotosensitive element from said opening.

9. In an automotive vehicle, a light collector for a headlamp dimmingdevice comprising a housing having an opening therein, a photosensitiveelement in said housing facing said opening, means for directing lightfrom said opening to said photosensitive element, said means comprisinga spherical light condensing lens in said opening, an opaque partitionhaving a horizontally disposed elongated aperture therein positioned insaid housing between said opening and said photosensitive element anddividing said housing into two compartments, said aperture being locatedsubstantially at the focal plane of said lens in alignment with saidlens and said photosensitive element and providing the sole means foradmitting light to said photosensitive element from said opening, and anadjustable support on said housing securing said light collector on saidvehicle so that said aperture is positioned to admit to saidphotosensitive element only that light approaching said vehicle fromwithin predetermined horizontal angles to the left and right of thefocal axis of said lens and from within predetermined vertical anglesabove and below the focal axis of said lens, the predetermined verticalangle below said focal axis being smaller than the predetermined angleabove said focal axis.

10. A light collector for a vehicle headlamp dimming device comprising ahousing having an opening therein, adjustable mounting means on saidhousing adapted to cooperate with said vehicle for adjustably securingsaid collector on said vehicle so that said opening faces toward thefront of the vehicle for the reception of light, a horizontally disposedelongated photosensitive element in said housing facing said opening andmeans for directing light from sources in front of the vehicle on whichsaid collector is mounted to said photosensitive element, saidlastmentioned means comprising a spherical light condensing lens in saidopening and an opaque partition having a horizontally disposed elongatedaperture therein positioned in said housing between said opening andsaid photosensitive element and dividing said housing into twocompartments, said aperture being located substantially at the focalplane of said lens in alignment with said lens and said photosensitiveelement and providing the sole means for admitting light to saidphotosensitive element from said opening.

11. A light collector for a vehicle headlamp dimming device comprising ahousing having an opening therein, adjustable mounting means on saidhousing adapted to cooperate with said vehicle for adjustably securingsaid collector on said vehicle so that said opening faces toward thefront of the vehicle for the reception of light, a photosensitiveelement in said housing facing said opening and means for directinglight from sources in front of the vehicle on which said collector ismounted to said photosensitive element, said last-mentioned meanscomprising a cylindrical light condensing lens in said opening, anopaque partition having a horizontally disposed elongated aperturetherein positioned in said housing between said opening and saidphotosensitive element and dividing said housing into two compartments,said aperture being located substantially at the focal plane of saidlens in alignment with said lens and said photosensitive element andproviding the sole means for admitting light to said photosensitiveelement from said opening, and a pair of reflectors angularly disposedon opposite sides of said aperture and between said aperture and saidlens.

References Cited in the file of this patent UNITED STATES PATENTS801,766 Churchill Oct. 10, 1905 1,935,698 Decker et a1. Nov. 21, 19332,013,594 Zworykin Sept. 3, 1935 2,182,987 Hopkins Dec. 12, 19392,207,097 Logan July 9, 1940 2,208,016 Cowles July 16, 1940 2,375,677Moore May 8, 1945 2,413,208 Barnes Dec. 24, 1946 2,442,240 Hooker et a1May 25, 1948

